The principle of the cycle with ejector, as known in the prior art, is briefly summarized hereinafter.
A driving fluid at high pressure and high temperature, supplied from a boiler, is expanded in the first section of an ejector. The expansion results in a speeding up of said fluid which may thus drive along therewith a second fluid flowing from an evaporator. Both fluids are admixed and penetrate the second section of the ejector. By reducing their velocity or kinetic energy, their pressure is increased up to that prevailing in the condenser. A heat source supplies heat at high temperature BT to the boiler, a second heat source, which may be the external surrounding medium, supplies heat at low temperature (ET) to the evaporator, so that the sum of the two heat supplies is recoverable at the condenser at an intermediary temperature CT. The fluid flowing out from the condenser is partly expanded and again evaporated at temperature ET, and partly increased in pressure through a pump and vaporized in the boiler at temperature BT.